Rimava (Hungarian: Rima) is a river in southern central Slovakia, which flows only in the Rimavská Sobota District. It is a right tributary of the Slaná river. The Rimava is 83 km (52 mi) long and its basin size is 1,378 km (532 sq mi).

Its source is in Veporské vrchy at approximately 1,130 m above sea level. It flows through the towns of Tisovec, Hnúšťa and Rimavská Sobota before merging into the Slaná river near Vlkyňa at 145 m a.s.l.